Kroó began his new, highly demanding career in 1957, with a freshly gained diploma in his pocket. As editor, and later senior editor of the Music Department of Hungarian Radio, he organised popular music education on radio, making it a successful radio genre. From this time onwards right to the end of his life he edited and made such series as The Composition of the Week and Let's Listen to it Together. He was the editor in charge of radio's New Musical Journal, in which for decades he reviewed the most important concerts of the week. His reviews were characterised by sure judgment, openness to talent and enthusiasm. Selections from his music criticisms were published in two volumes, in 1981 and 1999. He wrote almost without interruption. His books and articles deal with different periods of music history. (Schumann, 1958; Berlioz, 1960; Bartók's works written for the stage, 1962; The "liberating" opera, 1966; Wagner, 1968; Guide to Bartók, 1971; The 25 or 30 years of Hungarian composition, 1971; Aladár Rácz, 1979; Heilawac – Wagner studies, 1983; The first year of pilgrimage – Liszt study, 1986; Bence Szabolcsi I-II, 1994).
György Kroó was not a specialist, ivory tower scholar. His wide sphere of interests, imposing knowledge of languages, rapid and intensive absorption of music, theatre, literature and the visual arts equipped him to make frequent pronouncements on important subjects and interconnections. There were no subject barriers as far as he was concerned: he could give enjoyable radio lectures on the most complex matters, and even seemingly simple questions moved him to vast works of scholarship. He felt music in his bones, and could transmit his sensations fully both verbally and in writing. This was the secret of his remarkably suggestive teaching (from 1961 as teacher of music history and from 1972 to the end of his life as head of the musicology department). He had a key to the soul, that certain sixth sense, which helped him to perceive greater depths than others. He taught generations, not only in the musicology department, but also – instrumental musicians – in his general music history classes. His inspired teaching made a lasting impression on his students.
He was awarded the Erkel Prize (1963), the SZOT Prize (1970), and the Széchenyi Prize (1995).